January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Mar 28, 2024 11:45 am

All times are UTC - 4 hours




Post new topic Reply to topic  [ 4 posts ] 
Author Message
 Post subject: GMII lock mechanism
PostPosted: Mon Jan 15, 2018 1:47 pm 
Offline
Active Member

Joined: Wed Jul 21, 2010 1:23 pm
Posts: 99
Location: San Luis Obispo County, CA
I am having troubles with the lock mechanism on my GMII. If I don't push it in really hard when it is on the lower half of the protractor, I risk having it slip. If I do get it set well enough, it is difficult to unlock later when I want to change the angle.

I assume this is due to wear on the pieces involved. Is there a reasonable fix?

_________________
Mary M. Rafferty
http://gems.vistagrande.com


Top
 Profile  
Reply with quote  
 Post subject: Re: GMII lock mechanism
PostPosted: Mon Jan 15, 2018 4:47 pm 
Offline
Gold Member
User avatar

Joined: Sat Sep 29, 2007 8:14 pm
Posts: 1383
Location: Royal Oak, Michigan US
vistagrande wrote:
I am having troubles with the lock mechanism on my GMII. If I don't push it in really hard when it is on the lower half of the protractor, I risk having it slip. If I do get it set well enough, it is difficult to unlock later when I want to change the angle.

I assume this is due to wear on the pieces involved. Is there a reasonable fix?

Hi Mary,
If you can send me an email (in my profile) or a pm with a photo of the exact item you believe is creating the issue, I may have a spare. In addition, can go on my website and send me an email through there.

_________________
Warm regards,
Roger Dery
Royal Oak, Michigan US
http://www.rogerdery.com


Top
 Profile  
Reply with quote  
 Post subject: Re: GMII lock mechanism
PostPosted: Mon Jan 15, 2018 7:29 pm 
Offline
Active Member

Joined: Wed Jul 21, 2010 1:23 pm
Posts: 99
Location: San Luis Obispo County, CA
I am not actually sure which part is causing the issue. Parts include the machine operator of course.

Since my initial post I once again found the wonderful thread you started on Fac-Ette maintenance some years ago. I was thinking that it was what you called the "clamp arm" in the post at
viewtopic.php?p=146702#p146702

However, after seeing your photo, I got brave enough to roll the saddle block off the protractor and unscrew that part. There was nothing obvious there. The brass "lock nut" did not want to come out for inspection and I was reluctant to apply much in the way of force for fear I would make matters worse.

I don't have a clear idea of how the Saddle block locks in place. In addition to the clamp arm screw / brass lock nut, there are the two set screws which limit movement of the block. Are we locking the block in place simply by tiny changes in a horizontal slit that is seen on the protractor side of the block?

_________________
Mary M. Rafferty
http://gems.vistagrande.com


Top
 Profile  
Reply with quote  
 Post subject: Re: GMII lock mechanism
PostPosted: Mon Jan 15, 2018 8:49 pm 
Offline
Gold Member
User avatar

Joined: Sat Sep 29, 2007 8:14 pm
Posts: 1383
Location: Royal Oak, Michigan US
vistagrande wrote:
I am not actually sure which part is causing the issue. Parts include the machine operator of course.

Since my initial post I once again found the wonderful thread you started on Fac-Ette maintenance some years ago. I was thinking that it was what you called the "clamp arm" in the post at
viewtopic.php?p=146702#p146702

However, after seeing your photo, I got brave enough to roll the saddle block off the protractor and unscrew that part. There was nothing obvious there. The brass "lock nut" did not want to come out for inspection and I was reluctant to apply much in the way of force for fear I would make matters worse.

I don't have a clear idea of how the Saddle block locks in place. In addition to the clamp arm screw / brass lock nut, there are the two set screws which limit movement of the block. Are we locking the block in place simply by tiny changes in a horizontal slit that is seen on the protractor side of the block?

Hi Mary,
Unscrewing the 'clamping screw' should not be an issue, and is something worth doing from time to time to clean up any residue. I clean it with denatured alcohol, and re-lube it lightly with 'white grease' like you would find in an auto parts store. Usually a small tube containing 2 or 3 ounces (which will last several lifetimes).

Re locking the saddle block in place - there are two black locking hex-head screws on either end of the saddle block. Normally, they should NOT need adjustment, as they are there to 'guide' or 'control' the movement, not stop the saddle block movement. The center screw, with the angled handle, is the only tightening unit you should be using. If it is no longer holding the saddle block movement in place, then it is time to replace the brass locking nut. And, this is not a big deal.

The brass lock nut is normally the weakest link. If it is determined to be the cause of your saddle block issue, I have a few spares and would be willing to send you one. To remove the locking nut, once you have the saddle block off, and unscrewed the locking nut, you should be able to easily (and lightly) tap on it and it should push through and fall out.

Then you can inspect it to see about the level of wear.

The replacement will take a bit of calculating to ensure the opening of the screw hole lines up with the locking nut as it advances through the opening to reach the brass lock nut. I would normally mark the area on the outside of the brass with a magic marker to ensure easier line up.

Hope you find this helpful.

_________________
Warm regards,
Roger Dery
Royal Oak, Michigan US
http://www.rogerdery.com


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: Google [Bot] and 34 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock